No display on external USB-C monitor after i915kms is loaded

[DanielCervus]

Describe the bug
My external USB-C display is working fine under UEFI GOP driver, but after loading i915kms driver, the external screen goes blank and the internal screen on laptop still works. The last line of dmesg is "drmn0: [drm] ERROR Link Training Unsuccessful".

FreeBSD version
FreeBSD DevilDeer 13.2-RELEASE-p8 FreeBSD 13.2-RELEASE-p8 GENERIC amd64 1302001 1302001

PCI Info

pciconf -lv

hostb0@pci0:0:0:0: class=0x060000 rev=0x02 hdr=0x00 vendor=0x8086 device=0x9a14 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = '11th Gen Core Processor Host Bridge/DRAM Registers' class = bridge subclass = HOST-PCI vgapci0@pci0:0:2:0: class=0x030000 rev=0x03 hdr=0x00 vendor=0x8086 device=0x9a49 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'TigerLake-LP GT2 [Iris Xe Graphics]' class = display subclass = VGA none0@pci0:0:4:0: class=0x118000 rev=0x02 hdr=0x00 vendor=0x8086 device=0x9a03 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'TigerLake-LP Dynamic Tuning Processor Participant' class = dasp pcib1@pci0:0:6:0: class=0x060400 rev=0x02 hdr=0x01 vendor=0x8086 device=0x9a09 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = '11th Gen Core Processor PCIe Controller' class = bridge subclass = PCI-PCI pcib2@pci0:0:7:0: class=0x060400 rev=0x02 hdr=0x01 vendor=0x8086 device=0x9a23 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Thunderbolt 4 PCI Express Root Port' class = bridge subclass = PCI-PCI none1@pci0:0:8:0: class=0x088000 rev=0x02 hdr=0x00 vendor=0x8086 device=0x9a11 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'GNA Scoring Accelerator module' class = base peripheral none2@pci0:0:10:0: class=0x118000 rev=0x01 hdr=0x00 vendor=0x8086 device=0x9a0d subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tigerlake Telemetry Aggregator Driver' class = dasp xhci0@pci0:0:13:0: class=0x0c0330 rev=0x02 hdr=0x00 vendor=0x8086 device=0x9a13 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Thunderbolt 4 USB Controller' class = serial bus subclass = USB none3@pci0:0:13:2: class=0x0c0340 rev=0x02 hdr=0x00 vendor=0x8086 device=0x9a1b subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Thunderbolt 4 NHI' class = serial bus subclass = USB pcib3@pci0:0:14:0: class=0x010400 rev=0x00 hdr=0x00 vendor=0x8086 device=0x9a0b subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Volume Management Device NVMe RAID Controller' class = mass storage subclass = RAID none4@pci0:0:18:0: class=0x070000 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0fc subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Integrated Sensor Hub' class = simple comms subclass = UART xhci1@pci0:0:20:0: class=0x0c0330 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0ed subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP USB 3.2 Gen 2x1 xHCI Host Controller' class = serial bus subclass = USB none5@pci0:0:20:2: class=0x050000 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0ef subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Shared SRAM' class = memory subclass = RAM iwlwifi0@pci0:0:20:3: class=0x028000 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0f0 subvendor=0x8086 subdevice=0x4070 vendor = 'Intel Corporation' device = 'Wi-Fi 6 AX201' class = network ig4iic0@pci0:0:21:0: class=0x0c8000 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0e8 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Serial IO I2C Controller' class = serial bus ig4iic1@pci0:0:21:1: class=0x0c8000 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0e9 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Serial IO I2C Controller' class = serial bus none6@pci0:0:22:0: class=0x078000 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0e0 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Management Engine Interface' class = simple comms isab0@pci0:0:31:0: class=0x060100 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa082 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP LPC Controller' class = bridge subclass = PCI-ISA hdac0@pci0:0:31:3: class=0x040100 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0c8 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP Smart Sound Technology Audio Controller' class = multimedia subclass = audio ichsmb0@pci0:0:31:4: class=0x0c0500 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0a3 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP SMBus Controller' class = serial bus subclass = SMBus none7@pci0:0:31:5: class=0x0c8000 rev=0x30 hdr=0x00 vendor=0x8086 device=0xa0a4 subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' device = 'Tiger Lake-LP SPI Controller' class = serial bus vgapci1@pci0:1:0:0: class=0x030200 rev=0xa1 hdr=0x00 vendor=0x10de device=0x1f97 subvendor=0x1028 subdevice=0x0b23 vendor = 'NVIDIA Corporation' device = 'TU117M [GeForce MX450]' class = display subclass = 3D none8@pci65532:224:28:0: class=0x088000 rev=0x00 hdr=0x00 vendor=0x8086 device=0x09ab subvendor=0x0000 subdevice=0x0000 vendor = 'Intel Corporation' device = 'RST VMD Managed Controller' class = base peripheral pcib4@pci65532:224:28:4: class=0x060400 rev=0x30 hdr=0x01 vendor=0x8086 device=0xa0bc subvendor=0x1028 subdevice=0x0b23 vendor = 'Intel Corporation' class = bridge subclass = PCI-PCI nvme0@pci65532:225:0:0: class=0x010802 rev=0x00 hdr=0x00 vendor=0x1e0f device=0x0001 subvendor=0x1e0f subdevice=0x0001 vendor = 'KIOXIA Corporation' device = 'NVMe SSD Controller BG4' class = mass storage subclass = NVM

DRM KMOD version
drm-510-kmod 5.10.163_7
drm-kmod 20220907_1

To Reproduce
Plug in DELL P2423DE to the laptop through USB-C/DP port, boot up, then "#kldload i915kms".

Additional context
The drm driver is successfully loaded and the console has been replaced with vt. Everything works fine when the external monitor is not connected, and the only difference of dmesg is that it doesn't contain that line of error message.